1). Field of the Invention
This invention relates generally to a system for burn-in testing of electronic devices.
2). Discussion of Related Art
When fabrication of electronic devices, such as computer processors and memories, has been completed, the electronic devices are subjected to burn-in and electrical tests in order to identify and eliminate defective devices before shipment to customers. The term xe2x80x9cburn-inxe2x80x9d relates to operation of an integrated circuit at a predetermined temperature or temperature profile, typically an elevated temperature in an oven. Certain operating electrical bias levels and/or signals are supplied to the electronic devices while they are at the elevated temperature. The use of the elevated temperature accelerates stress to which the devices are subjected during burn-in, so that marginal devices that would otherwise fail shortly after being placed in service fail during burn-in, and are eliminated before shipping.
The electronic devices are usually located within burn-in sockets that are mounted to a burn-in board substrate. The burn-in board substrate is then inserted into an oven, and edge fingers on the burn-in board substrate are inserted into an edge finger socket in a rear of the oven. A driver board assembly is located externally of the oven, and is connected to the edge finger socket on a feedthrough board. Signal currents are provided from the driver board assembly through the feedthrough board, the edge finger socket on the feedthrough board, and the edge fingers to the electronic devices in the sockets on the burn-in board substrate. Power current is also provided from the driver board assembly through the socket and the edge fingers to the electronic devices.
The magnitude of the power that can be provided through edge fingers is generally relatively small, typically on the order of 3 to 5 A per finger. Certain devices, for example, computer processors, now require power currents having larger magnitudes than what can practically be achieved through edge finger connectors. In many cases, it may also be required to monitor power current that is provided to each individual device. Existing systems, however, are not adapted for providing individual power current to individual devices, and therefore also do not lend themselves to monitoring of power currents that are provided individually to each electronic device per finger.
Another disadvantage of using edge finger connectors is that they can only be located on an edge of a substrate, and therefore provide a limited amount of real estate for adding additional signal, power, ground, and other lines.
Generally speaking, a system is provided which allows for burn-in testing of electronic devices wherein power current is provided individually to each one of the electronic devices. The system also includes various connectors, cables, and other configurations that allow for power currents having large magnitudes to be provided to the electronic devices.
According to one aspect of the invention, a burn-in board assembly is provided. The burn-in board assembly has a burn-in board substrate, a plurality of burn-in sockets on the burn-in board substrate, each to receive a respective electronic device. The burn-in board assembly also has a plurality of burn-in board signal connectors on the burn-in board substrate. Each burn-in board signal connector has a surface for releasably mating with a respective surface of a respective signal contact. Each signal connector is capable of carrying maximum direct current having a first magnitude. (Direct-current ratings are used throughout this description, although it should be understood that the connectors that are so characterized herein may carry direct current or alternating current.) The burn-in board assembly also has a plurality of burn-in board signal conductors. Each signal conductor connects the burn-in board signal connectors to signal contacts on the devices. The burn-in board assembly also has a plurality of burn-in board power connectors secured to the burn-in board substrate. Each burn-in board power connector has a surface for releasably mating with a respective surface of a respective power contact. Each power connector is capable of carrying maximum direct current having a second magnitude which is larger than the first magnitude. The burn-in board assembly also has a plurality of burn-in board power conductors. Each burn-in board power conductor connects each burn-in board power connector individually to a respective burn-in board power contact on a respective one of the devices.
The second magnitude may be at least 7 A. The second magnitude may be at least 1.5 times the first magnitude. The second magnitude may be at least 4 A more than the first magnitude.
The burn-in board power conductors are preferably capable of carrying maximum direct current of a magnitude which is larger than the first magnitude.
Burn-in board power conductors preferably connect at least five of the burn-in board power connectors individually to at least five of the devices. More preferably, the burn-in board power conductors connect at least 10 of the burn-in board power connectors individually to at least 10 of the devices.
The burn-in board signal connectors and the burn-in board power connectors may be different types of connectors. The burn-in board signal connectors may, for example, be edge fingers. The surface of each burn-in board power connector may, for example, be cyndrical, preferably circular cylindrical, such as when the burn-in power connector is a respective pin.
The burn-in board signal connectors and the burn-in board power connectors may be in two distinct groups. The burn-in board assembly may, for example, include a burn-in board power connector block with the burn-in board power connector secured to the burn-in board power block, and the burn-in board power connector block being secured to the burn-in board substrate independent from the burn-in board signal connectors. The burn-in board assembly may also include a burn-in board daughter card, with the burn-in board power connector being secured to the burn-in board daughter card, and the burn-in board daughter card being secured to the substrate independent from the burn-in board signal connectors. Portions of the burn-in board power conductors may form traces, the traces spreading from one another from the burn-in board power connectors to locations where the burn-in board power conductors leave the burn-in board daughter card. The traces may spread by at least 25%.
Preferably, movement of the burn-in board substrate in an insertion direction causes engagement of the burn-in board signal connectors with the signal contacts and engagement of the burn-in board power connectors with the power contacts. In such a case, the burn-in board power connectors may be pins, and the burn-in board signal connectors may be edge fingers.
Preferably, the signal contacts are at the same locations on at least two of the devices, and the power contacts are at the same locations on the two devices.
According to another aspect of the invention, a burn-in board assembly is provided, having different types of connectors. A plurality of burn-in board signal edge finger connectors and a plurality of burn-in board power conductors may be secured to a burn-in board substrate, wherein each burn-in board power conductor has a cylindrical contact surface. The cylindrical contact surface may, for example, be circular cylindrical. In one embodiment, the burn-in board power conductors may be pins. An embodiment is also contemplated wherein the burn-in board power conductors are holes that mate with pins, but such an embodiment has the disadvantage that the pins cannot be maintained as easily as when they are located on the burn-in board substrate.
According to another aspect of the invention, a burn-in testing driver assembly is provided. The burn-in testing driver assembly includes a driver substrate, a plurality of driver signal connectors secured to the driver substrate, signal electronics, a plurality of driver power connectors secured to the driver substrate, and a power supply. Each driver signal connector has a surface for releasably mating with a respective signal contact. Each driver signal connector is also capable of carrying a maximum direct current having a first magnitude. Each driver power connector has a surface for releasably mating with a respective power contact. Each driver power connector is also capable of carrying maximum direct current having a second magnitude which is larger than the first magnitude. The power supply is connected to the driver power connectors.
The second magnitude may, for example, be at least 7 A. The second magnitude may, for example, be at least 1.5 times the first magnitude. The second magnitude may, for example, be at least 4 A more than the first magnitude.
The driver signal connectors and the driver power connectors may be different types of connectors. The driver signal connectors may, for example, be within an edge finger connector block. The surface of each driver power connector may, for example, be substantially circular, such as in the case where each driver power connector is a respective pin.
The driver signal connectors and the driver power connectors may be in two distinct groups. The burn-in testing driver may, for example, further include a driver power connector block, with the driver power connectors being secured to the driver power connector block, and the driver power connector block being secured to the driver substrate independent from the driver signal connectors. The burn-in testing driver may, for example, further include a driver power board, with the driver power connector being secured to the driver power board, and the driver power board being secured to the driver substrate independent from the driver signal connectors.
Preferably, movement of the driver substrate in an insertion direction causes engagement of the driver signal connectors with the signal contacts and engagement of the driver power connectors with the power contacts.
The burn-in testing driver may further include a plurality of driver current detectors and an output device. Each detector may be in communication with a respective one of the driver power connectors to detect current separately through each one of the driver power connectors. The output device may be in communication with the driver current detectors to provide an output of the respective currents through the respective driver power connectors.
According to a further aspect of the invention, a burn-in testing driver assembly is provided, having a driver substrate, a plurality of driver signal connectors, signal electronics, a plurality of driver power connectors, a power supply, a plurality of driver current detectors, and an output device. The driver signal connectors are secured to the driver substrate. Each driver signal connector has a surface for releasably mating with a respective signal contact. The signal electronics is connected to the driver signal connectors. The driver power connectors are secured to the driver substrate. Each driver power connector has a surface for releasably mating with a respective power contact. The power supply is connected to the driver power connectors. Each detector is in communication with a respective one of the driver power connectors to detect current separately through each one of the driver power connectors. The output device is in communication with the driver current detectors to provide an output of the respective current through the respective driver connectors. The output device may, for example, be a microcontroller that provides an output indicative of the magnitudes of the respective currents to a computer.
Preferably, power current provided by the power supply to a plurality of the driver power connectors is shut down if a current detected by a single driver current detectors exceeds a predetermined maximum. Preferably, power current to at least 10 of the driver power connectors is shut down. Power current may be shut down by shutting down the power supply.